Tube Amp Archive

Assuming he was buying the stuff off the shelf, does Permatex come with a use by date? Probably not but it seems we have a better idea of when the amps were built. Providing the stuff doesn't become hygroscopic or go brittle with age and heat, does it really matter? Is this for a restoration, or a n...

Using Firefox. Running okay. Notifications are displaying for me as well.

Also, trying to post the above, it duplicated itself.

Now, when trying to edit, I got this:

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Czech Republic. I've been having issues for about the same length of time. This, just now: Internal Server Error The server encountered an internal error or misconfiguration and was unable to complete your request. Please contact the server administrator at webmaster@ampgarage.neampfest.com to infor...

Chase Bliss are discontinuing five pedals in the EEA because of a lapsed exemption on Cadmium Sulfide in LDRs (Vactrols if you are a Marshall dude) These find their way into all kinds of products so I wanted to bring this to your attention in case you are anxious about supply issues. The story is th...

hi all - anyone have an opinion on the following OT question ? I'm using some basler trannies from a 100w peavey deuce [474v@30mA] , for a 102/183 type ODS but the OT only has 4ohm output , I have a 1x12 cab with a 16ohm G12-65 - everything I do I gets miced up so not really at risk of blowing it ,...

A schematic with your mods might be more helpful here. Not assuming you've done anything "wrong" just, it's a whole lot easier to reference from.

What is the voltage at the speaker output jack? With a signal and the amp dialed up to clipping.

RIP John Mayall

I do have the chassis out and I have measured plate voltage, Center tap voltage and OT resostance... But My multimeter is not precise enough. I don't get decimals o any of those readings so calculating Voltage drop and then calculating VD/R is not workable because my results are not precise. Talk u...

All of the parameters you need can be accessed by pulling the chassis out and proving the voltages and resistances needed for calculations. That said, if you are not willing to go that far then you have to live with limited results. Pulling a chassis out is five minutes of a job - nothing! Whether ...

I am in the habbit of changing amps often. They come and go as I try different things. I like to get new tubes on them usually and so need to bias them properly. Not every amp is built equally and some times, getting to the contatcs to make the measurement is a pain. Enter the idea of Bias probes. ...

I slipped up with the form B relays in the previous post, the circuit should use form A (normally open until energised)... moving on. Again, the channel control circuit has very little interaction with the audio signal which uses optocouplers with a low on-resistance. The optocouplers themselves req...

Building by the numbers...hmm! I can't imagine anyone who ever did that found the sound they were looking for. There are some qualities of resistors we can take to the bank as it were, but the real Q factor is down to your critical listening skills paired with your musical intelligence. You might as...

Something along the lines of a feasibility study, I drew up the schematic for an onboard solid state ABY mixer for the 5E3/Tweedle Dee. I don't have anything against solid state per se but it's easy to suck the tone right out of an amp circuit with it and it needs careful handling. The ABY circuit I...

Or get yourself a small arbor press.